The New Rarest Shark Tooth in My Collection: Lower Glen Rose

[Mikrogeophagus]

Today I took a spur of the moment trip up to the Canyon Lake area for some hunting in the lower Glen Rose. My first venture into the region took place last year and was only a limited success in that I scored a measly two micro echinoids. The plan for today was to try some new spots in hopes of striking the perfect layer of echinoid diversity. The first site was a complete bust, but the second immediately showed promise when I noticed the ground was littered with broken bits of thin echinoid test.

 

Because I had arrived so close after the recent rains, the ground was still a sticky slop of Glen Rose mud. The combination of running along the slopes and frequent crouching set my calves on fire, but the scent of urchins kept me on the chase. Very quickly I was lucky to encounter some really nice crab claws from Pagurus banderensis. A couple had both pincers still preserved. Surprisingly common was also the tiny crushing dentition of Pycnodont fish. They aren't all that interesting to look at, but the simple fact that vertebrate material was present gave me daydreams of finding an elusive Glen Rose shark tooth. I tried to shake away such a hopeless goal, but it continued to sit in my mind. After a couple hours, I found an Amiid fish tooth and some star-shaped Isocrinus annulatus columns. 

 

For whatever reason, I could not find a single echinoid spine, let alone a complete test. I was searching the ground very closely, so my thinking was it may be more to do with the site than myself. As I was doing the usual close inspection, I snuck up on a black figure nestled securely in a pile of Glen Rose matrix. It took a moment to register that I wasn't looking at just another chunk of black bug. 

 

 

I safely stashed the two pieces of Polyacrodus. Sadly, the third fragment was nowhere to be seen despite my best efforts. After finding some more crab claws it was time to head out. On the trek to the car, I spotted a Trigonia whitneyi? clam, maybe from the upper Glen Rose.

 

 

 

I'm not sure what species this is. I see Polyacrodus aff. parvidens is described form the Texas Albian up north. Other than that, there doesn't seem to be much info. I've seen some discussion on Polyacrodus brevicostata being a possibility as well.

 

Top L to R: Trigonia whitneyi? and Pagurus banderensis

Bottom L to R: Amiid tooth, Pycnodont teeth, Isocrinus annulatus

 

It seems my streak of urchin unluckiness has continued, but I'll take a Polyacrodus any day of the week!

[siteseer]

Any time you can get more than half of a Polyacrodus crown, you can count yourself very lucky.  I've had to buy or trade for  a specimen like that.  Great find. 

[sixgill pete]

Fantastic find. That would be a welcome addition to most any collection. I always get a thrill finding any Hybodontiforme.

Edited January 27 by sixgill pete

[JamieLynn]

I've never even heard of this creature and as you know, I hunt the Glen Rose pretty extensively! Congrats on a stellar find!! 

[ThePhysicist]

Very nice!

[Mikrogeophagus]

8 hours ago, JamieLynn said:

I've never even heard of this creature and as you know, I hunt the Glen Rose pretty extensively! Congrats on a stellar find!! 

The best thing about fossil hunting imo is the chance to find those weirdos that were never even on the radar to begin with!

Edited January 28 by Mikrogeophagus

[LSCHNELLE]

You certainly have a knack at finding these small shark teeth. More than that you learn about them and know and share your knowledge. Congrats and thanks for sharing!